Word
insidious
Phoneticsin·sid·i·ous
US/ˌɪnˈsɪˌdiəs/
UK/ɪnsˈɪdɪəs/
Definitions
01gradually harmful
adj. developing slowly and secretly in a way that is harmful.
adj. proceeding in a gradual, subtle way, but with very harmful effects. Often used in medical or political contexts to describe something that is not immediately obvious.
“The disease was insidious, showing no symptoms until it was already very serious.”
“High blood pressure is often called an insidious condition because it can damage the heart for years without the patient feeling any different.”
Academic
02deceptive or treacherous
adj. tricky and dangerous because it looks attractive or harmless but is actually a trap.
adj. treacherous or crafty; intending to entrap or beguile by appearing harmless or alluring.
“The advertisement used insidious methods to make people spend money they did not have.”
“The propaganda was insidious, slowly changing public opinion by presenting half-truths as established facts.”
Formal · Literary
Synonyms
Antonyms
Real-World Examples
“It’s a play that’s less about toxic masculinity and insidious racism than women’s response to it.” “This year, Russia started “direct attacks on civilian locomotives”, he said – an insidious tactic, at a time when Ukraine is short of air defences.” Etymology
From Middle French insidieux, from Latin īnsidiōsus (“cunning, artful, deceitful”), from īnsidiae (“a lying in wait, an ambush, artifice, stratagem”) + -ōsus, from īnsideō (“to sit in or on”), from in (“in, on”) + sedeō (“to sit”).
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.
Scan code
englishreference.com/q/insidious